Re: [PATCH v2] infiniband: remove WARN that is not kernel bug

Leon Romanovsky
2016-11-21T17:38:27Z

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On Mon, Nov 21, 2016 at 09:52:53AM -0700, Jason Gunthorpe wrote:
> On Mon, Nov 21, 2016 at 02:14:08PM +0200, Leon Romanovsky wrote:
> > >
> > > In ib_ucm_write function there is a wrong prefix:
> > >
> > > + pr_err_once("ucm_write: process %d (%s) tried to do something hinky\n",
> >
> > I did it intentionally to have the same errors for all flows.
>
> Lets actually use a good message too please?
>
> pr_err_once("ucm_write: process %d (%s) changed security contexts after opening FD, this is not allowed.\n",
>
> Jason

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From 70f95b2d35aea42e5b97e7d27ab2f4e8effcbe67 Mon Sep 17 00:00:00 2001
From: Leon Romanovsky <leonro@mellanox.com>
Date: Mon, 21 Nov 2016 13:30:59 +0200
Subject: [PATCH rdma-next V2] IB/{core, qib}: Remove WARN that is not kernel bug

WARNINGs mean kernel bugs, in this case, they are placed
to mark programming errors and/or malicious attempts.

BUG/WARNs that are not kernel bugs hinder automated testing efforts.

Signed-off-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>

---
* Improved error prints.
---
drivers/infiniband/core/ucm.c | 5 ++++-
drivers/infiniband/core/ucma.c | 5 ++++-
drivers/infiniband/core/uverbs_main.c | 5 ++++-
drivers/infiniband/hw/qib/qib_file_ops.c | 5 ++++-
4 files changed, 16 insertions(+), 4 deletions(-)

diff --git a/drivers/infiniband/core/ucm.c b/drivers/infiniband/core/ucm.c
index 7713ef0..579f9a7 100644
--- a/drivers/infiniband/core/ucm.c
+++ b/drivers/infiniband/core/ucm.c
@@ -1104,8 +1104,11 @@ static ssize_t ib_ucm_write(struct file *filp, const char __user *buf,
struct ib_ucm_cmd_hdr hdr;
ssize_t result;

- if (WARN_ON_ONCE(!ib_safe_file_access(filp)))
+ if (!ib_safe_file_access(filp)) {
+ pr_err_once("ucm_write: process %d (%s) changed security contexts after opening file descriptor, this is not allowed.\n",
+ task_tgid_vnr(current), current->comm);
return -EACCES;
+ }

if (len < sizeof(hdr))
return -EINVAL;
diff --git a/drivers/infiniband/core/ucma.c b/drivers/infiniband/core/ucma.c
index 9520154..e12f8fa 100644
--- a/drivers/infiniband/core/ucma.c
+++ b/drivers/infiniband/core/ucma.c
@@ -1584,8 +1584,11 @@ static ssize_t ucma_write(struct file *filp, const char __user *buf,
struct rdma_ucm_cmd_hdr hdr;
ssize_t ret;

- if (WARN_ON_ONCE(!ib_safe_file_access(filp)))
+ if (!ib_safe_file_access(filp)) {
+ pr_err_once("ucma_write: process %d (%s) changed security contexts after opening file descriptor, this is not allowed.\n",
+ task_tgid_vnr(current), current->comm);
return -EACCES;
+ }

if (len < sizeof(hdr))
return -EINVAL;
diff --git a/drivers/infiniband/core/uverbs_main.c b/drivers/infiniband/core/uverbs_main.c
index 44b1104..38c79ad 100644
--- a/drivers/infiniband/core/uverbs_main.c
+++ b/drivers/infiniband/core/uverbs_main.c
@@ -746,8 +746,11 @@ static ssize_t ib_uverbs_write(struct file *filp, const char __user *buf,
int srcu_key;
ssize_t ret;

- if (WARN_ON_ONCE(!ib_safe_file_access(filp)))
+ if (!ib_safe_file_access(filp)) {
+ pr_err_once("uverbs_write: process %d (%s) changed security contexts after opening file descriptor, this is not allowed.\n",
+ task_tgid_vnr(current), current->comm);
return -EACCES;
+ }

if (count < sizeof hdr)
return -EINVAL;
diff --git a/drivers/infiniband/hw/qib/qib_file_ops.c b/drivers/infiniband/hw/qib/qib_file_ops.c
index 382466a..2d1eacf 100644
--- a/drivers/infiniband/hw/qib/qib_file_ops.c
+++ b/drivers/infiniband/hw/qib/qib_file_ops.c
@@ -2066,8 +2066,11 @@ static ssize_t qib_write(struct file *fp, const char __user *data,
ssize_t ret = 0;
void *dest;

- if (WARN_ON_ONCE(!ib_safe_file_access(fp)))
+ if (!ib_safe_file_access(fp)) {
+ pr_err_once("qib_write: process %d (%s) changed security contexts after opening file descriptor, this is not allowed.\n",
+ task_tgid_vnr(current), current->comm);
return -EACCES;
+ }

if (count < sizeof(cmd.type)) {
ret = -EINVAL;
--
2.7.4

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